Machine for grinding the teeth of milling-cutters by means of rotating grinding-wheels in particular of the teeth of spiral milling-cutters.



G. BENICKE. IIIA'CIIINE FOR GRINDING THE TEETH OF MILLING CUTTERS BY MEANS OF'ROTATING GR INDING WHE ELS IN PARTICULAR OF THE TEETH OF SPIRAL MILLING CUTTERS.

APPLICATION FILED DEC. 3. 191% s SHEETSSHEET l.

/ e. BENIGKE. MACHINE FOR GRINDING THE TEETH 0F MILLING CUTTERS BY MEANS OF ROTATING GRINDING WHEELS IN PARTICULAR OF THE TEETH 0F SPIRAL MILLING CUTTERS.

APPLICATION FILED DEC.3. 1914.

Patented July 17, 1917.

3 SHEETS-SHEET Z- m Nu m I G. BENICKE; MACHINE FOR GRINDING THE TEETH 0F MILLING CUTTERS BY MEANS OF ROTATING GRINDING WHEELS IN PARTICULAR OF THE TEETH 0F SPIRAL MILLING CUTTERS.

. I APPLICATION FILED DEC-Ih I9I4.

- Patented July 17, 1917.

3 SHEETS-SHEET 3.

0 d of Fig. 5

of construction by snares r rnnr 'nisisihn 3E036: BENICKE, 0F OFEENBhCH-ON-THE-MAIN, GERMANY, ASSIGNOR TO THE FIRM 0F 333,933?! QFIEEMBACHZEE SPEZIALFABRIK 3CHM ERGELWARENFABRIKATION MEYER 8r. $GHMIDT, 0F (JFFENBACH-ON-THE-MAIN, GERMANY.

MACHINE FOR GRINDING THE TEETH 0F MILLING-CUTTERS BY MEANS OF ROTATING:

GRINDING-JVfilfflfilhfi IN PARTICULAR OF THE TEETH OF SPIRAL MILLING-CUTTEES.

Specification of Letters Patent.

Patented July it, iditf.

Application filed December 2, ism. Serial No. 575,257.

To all whomit may concern:

Be it known that l, Gnono Bnnionn, a subject of the Emperor of Germany, residing at Uilenbach-on-the-Main, Germany, have invented new and useful improvements in machines for grinding the teeth of 'millingcutters by means of rotating grinding-wheels in particular of the teeth of spiral milling-cutters; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the artto which it appertains to make and use the same, reference being had to the accompanying draw- I ings, and toletters or figures of reference marked thereon, which form a part of this.

specification.

The grinding of milling cutters, especially those having helical teeth, was hitherto done with machines having a differential gear for imparting alternately during the grinding to the work piece a necessary movement for the turning of a single tooth and thereupon a feed motion for the following tooth, without putting the gear out of motion for the first movement. These machines are very expensive due to the differential gear necessary and as they have only had a single grinding support, the grinding requires a considerable long time which makes the grinding very expensive.

With the present invention these disadvantages are avoided. lhe two movements necessary for the turning of the teeth and for the feed; motion of the milling cutter are obtained withofit a" differential gear and in such a manner that the means for producing said movements always remain in gear. By'the use of more than one grinding support a higherproduction is obtained'than with machines hitherto known.

In the anneited drawin s is shown a form way o example.

Figure 1. s a vertical section on the line o--b of Fig. 5 showing ,a'front view of the grinding supports.

Fig. 2 is a side view of the bed showing the gearing for the feed motion. of the work piece.

- Fig' 3 is a vertical section on the line showing a side view of the grinding supports,

Fig. 4 is a front view of the bed showing adapted to be rotated in a horizontal plane.

This depending portion 6 has a horizontally arranged guide way Tin which is mounted. a slide 8, carrying a motor 9 mounted to swing on a horizontal axisnand carrying ,a grinding disk 10. It will thus be seen that the grinding disks may be adjusted in. any inclined position of their axes of rotation and moved laterally of the axis of the work piece 62 in the slides 7; moved toward and from the work piece by the slides 5, and moved longitudinally of said work piece by the slides 4.

4 The work piece 62 is held by vertical spindles 12 and it between dead centers and is driven by the driving plate 13. The upper head stock spindle is adjustable on the standard 3.

Long tools with relative small diameter will by the vertical arrangement not be bent as by the horizontal arrangements; the grinding wheels being arranged opposite etch other have the known advantage of compensating the bending stresses.

W'ork pieces with straight teeth are ground in the usual way by automatically moving the grinding supports up and down and by an automatic feeding of the work piece on to the next tooth at the end positions of the supports it the grinding disks have left the workpiece.

lit the workpiece has spiral wound teeth, of course a turning between the tool and the working piece around its longitudinal axis must take place during the up and down motion of the grinding supports.

piece according to the pitch of the screwthread like windings.

The feed motion of the work piece over the distance of one toothis etfected by change wheels at the end of the vertical stroke or path of the supports independent of the turning of the revolving table 2, said change wheels corresponding precisely with the circular pitch.

The workpiece is stationary during the grinding of the screw-thread like windings and is only turned for a single circular pitch during the feed motion on to the next tooth.

,The circular movement of the revolving table 2 with the contemporary up and down motion of the grinding supports el and 5 is obtainedin the following way.

The main driving shaft is driven bya belt pulley 15, on the end of which a bevel gear wheel 16 is keyed. A change gear is provided on the same main shaft, having a coupling box 19 slidable by a crank lever 20, (Fig. 5) on a key between two bevel gear wheels 17 and 18 toward the left or toward the right, thus capable of alternatively being coupled with the wheels 17 or 18 (Fig. l).

The bevel gear wheel 16 engages with the bevel gear wheel 21 which has a long hub with two spur gear wheels 22 and :23

keyed thereon.

From the spur gear wheel 22 the circular motion or the revolving table 2 for the purpose of grinding the screw thread like windings of milling cutters is derived; the spur gear wheel 23 causes the vertical movement of the grinding supports 1 and 5.

As can be seen from Fig. l the wheel 23 drives the spur gear wheels 26 and 27 through the medium of the two idle wheels 24 and 25. These spur gear wheels 26 and 27 are keyed on the vertical screw spindles 28 and 29, respectively causing by their rotation an up or down motion of the compound rests 4 and 5 with the grinding motors 9 according to the engagement of the coupling 19 on the main driving shaft with one of the bevel gear wheels 17 and 18.

Meanwhile the spur gear wheel 22 drives the spur gear wheel 30 keyed on the hub of the bevel gear wheel 31 and loosely mounted on a fixed journal pin within the bearing 32. This bevel gear wheel 31 engages with a bevel gear wheel 33 keyed on a horizontal shaft 35. Furthermore on the shaft 35 are keyed the spur gear wheel 34 for the driving of a self-acting feed that will afterward be described and also the change wheel 37 for the driving of the revolving table (Fig. 5).

As will be seen from the following, the spur gear Wheel 34. drives a spur gear wheel 40 by means of a back or countershaft gear 38 and 39 (Fig. 5). At the outside of the frame the controller 36 is keyed on the hollow shaft of the spur gear wheel 10 journaled in the frame 1. In the hollow shaft is loosely mounted the shaft al on which the reversing lever 42 (Fig. a) is keyed on the outside of the frame and the forkshaped lever 13 (Fig. 5) for the swinging of the cranklever 20 is also keyed on the shaft 11 inside of the frame.

Due to the stops i l (Fig. 4) adjustably fixed to the controlling wheel 36, which is turned by means of the hollow shaft of the wheel 10 the reversing lever 42 on'the shaft +t1 is swung in a known manner toward the left or toward the right, and with it by means of the forkshaped lever 13 also the cranklever 20, so that the latter alternatively couples the coupling 19 with the wheels 17 and 18. thus driving alternatively the bevel gear wheel 16 clockwise or counterclockwise and effecting the up and down motion. Simultaneously a shaft 45 (Fig. 5) is impelled by the change wheel 37 through the medium of a plurality of change wheels, corresponding to the spirallike pitch of the work piece. On the shaft 45 is mounted the worm 46 (Fig. 3) being in engagement with the worm wheel 17.

On the shaft of the worm wheel -17, journaled in the frame 1, is mounted the spur gear wheel 18 engaging a larger gear 19 concentrically fixed to the underside of the revolving table 2 and causing a turning to the left or to the right according to the engagement of the coupling 19 with one of the bevel gear wheels 17 or 18.

If no rotation of the revolving table 2 shall take place the wheel 37 (Fig. 5) is taken away, as in the case for work pieces with straight lined or square teeth.

The driving for the feed motion of the teeth is also derived from the main driving shaft in the following way: Next to the bevel gearwheel 18 (Fig. 1) rotating with the main driving shaft on the latter is keyed a belt pulley 50 (Figs. 1 and 5). This pulley 50 drives simultaneously by means of a so-called slipping belt a fixed pulleyf51 and a loose pulley 52 next thereto, both carried by a common, shaft. A spur gear wheel is keyed on the same shaft (Fig. 2) and a spur gear wheel 54 mounted on a shaft lying above the wheel 53 is in engagement with the latter and is fixed to a dividing plate 55 (Figs. 2 and 4).

Said dividing plate or disk 55 and the spur gear wheel 51 can only rotate, it by the adjustable stop 41 a catching rod (36 (F ig. a) is brought out of corresponding cavities in the dividing plate, thus leaving the latter free during one revolution. This movement of the rod 66 by the. controlling wheel 36 takes place simultaneously with the turning of the lever 12 by the controlling wheel 36, with the reversing of the revolvice lid

masses horizontal shaft 59 by the medium or a change gear.

A worm 60 in. engagement with. a worm wheel 61 on the shaft 12 is fixed to the inner end of the. shaft 59, the revolving table 2 forming the bearing of said shaft 12. If now the catching red 66 is brought out of vthe dividing disk 55 by the controlling wheel 36, the slipping belt driven by the pulley and guided by the loose pulley 52 will take with the fixed pulley 51 and a single revolution of the dividing disk takes place, whereupon the catching rod 66 again enters into a cavity of the dividing disk by a. spiral spring, (not shown). I

During this single revolution by the change wheel gear the worm wheeltll and also the shaft 12 with the driving plate 13 and the work piece is turned over the de sired circular pitch, said gear being chosen corresponding to the circular pitch of the work piece.

This operation only takes place if. re versed as has already been mentioned, that isif the supports have arrived atthe end ofltheimstroke and the grinding disks have left'the teeth of the work piece due to their vertical motion.

Thdmotions obtained by the two described drivingsto wit 1 the motion of the revolving table 2 with the grinding standards mounted thereon and 2 the up and down motion of the grinding standards enable the grinding. of work pieces with screw thread like or helical teeth. A further advantage obtained by the described driving is the almost mutual annulling of the non avoidable play of the several driving gears of the two driving mechanisms in such a manner, that the grinding disks come uniformly into contact as well during the upward motion as during the downward mo tion. The total play, that results from the driving means for the driving of the revolving table is composed of the plays of the wheels 22, 30, 31, 33 of the change gear wheels, drive by 37, further of the play of the triple Worn 46 within the worm wheel 4;? and of the play of the spur gear wheels l8, 4:9. The play of the driving gear of the vertical up and down motion of the supports is composed of the plays of the wheels 23, 24, 25, 26, 27 or the triple thread spindles 28, 29 with its nuts. Each of these two drivin s has a number of toothed wheels and one triple thread spindle, its number of lid threads and its pitch being entirely'equal so "that at each reversion the nonavoidable play within. thetwo separate driving gears can almost entirely compensate each other and consequently a uniform grinding can be M obtained.

What I wish to claim is:

I. A machine for grinding the teeth oi milling cutters having helical teeth, com.- prising means for vertically supporting the 5 cutter, grinding disks, a support for the latter, driving means for the disks, a table rigidly connected with the support, a movable member, means actuated by the latter to impart to the table and the grinding disks 30 carried by the latter, a revolving movement corresponding to the winding of the cutterte'eth relatively to the cutter, means actuated by said. movable member to impart a vertical reciprocating movement to the 35 grinding disks while they are moved around the cutter, means for feeding the latter relatively to the grinding disks to an amount corresponding to the circular pitch of its teeth, and 'a drive for actuating said mom; 99

be! and the feeding means for the cutter,

said feeding means being wholly independent of the means effecting a rotation of the table.

2. A machine for grinding the teeth of milling cutters having helical teeth, com prising means for supporting the cutter so that its axis lies in a vertical plane, grinding disks, a support for the latter, driving means for the disks, a table rigidly connect- 100 ed with the support, a sleeve provided with a toothed rim, a driving shaft adapted to rotate the sleeve, two members rigidly conncctcd to said sleeve, means actuated by one of said members for imparting a vcrtical reciprocating movement to the disks, sets of spur gearings and a worm gearing operatively connected to the second one of said members and adapted to impart to the table and the grinding disks carried by thew latter, a revolving movement corresponding to the winding of the cutter-teeth relatively to the stationary cutter, a gearing operatively connected to the means supporting the cutter and adapted to impart to the cutter a feed movement relatively to the grinding disks to an amount corresponding to the circular pitch of its teeth, an operative connection between said gearing and said driving shaft, said connection being wholly in dependent of the means transmitting the motion of the driving shaft to said sleeve and the means, eii'ecting a revolving movement of the table, means for locking the gearing for feeding the cutter as long as the grinding disks are engaging with the cutterteeth, and means operatively connected to the means effecting a rotation of the table for throwing out of action said locking means and adapted to change periodically of said supports, the latter being arranged in an eccentric manner relatively to the table and allowing a snnultaneous application of the grinding means, means for effecting a feed motion of the cutter, means for turning said. table, thus causing a relative movement between the cutteand the grinding means corresponding to the winding of the teeth during the feed movement of the grinding means along the circumference of the cutter while the latter is stationary, a driving member concentric to the axis of the cutter, threaded spindles mounted in said standard and each operatively connected with one of said supports for the grinding means, two sets of toothed gears operated by said member, one of the sets being adapted to rotate said spindles in the standard and the other set being adapted to impart a revolving motion to said table, a worm gear drive for turning the means sup porting the cutter to an amount correspondingto the circular pitch of the cutter teeth, said drive being independent of the turning means for said revolving table, a friction drive actuating said worm gear drive, and means for automatically throwing in and out said friction drive.

4. A machine for grinding the teeth of milling cutters having helical teeth, co1nprising means for supporting the cutter so that its axis lies in a vertical plane, a table, separate grinding means, a. drive for each grinding means, horizontally movable slides, each carrying a grinding means together with its drive, each grinding means and its means being adapted to pivot around a horizontal axis, brackets adapted to rotate about a vertical axis, each of said brackets carrying one of said slides, a slide with a horizontal guide-way for each of said brackets, a. standard provided with vertical guideways for the last mentioned guides, vertically threaded bolts operatively connected to the guides and supported in the stand ard, the uide-ways for said brackets being arranged in an eccentric manner relatively to the table, means for ettecting a feed motion of the cutter, means for turning said table to cause a relative movement between the cutter and the grinding means corresponding to the winding of the teeth during the feed movement of the grinding means along the circumference of the cutter while the latter is stationary, a driving member concentric to the axis of the cutter, two sets of toothed gears operated by said member, one of these sets being adapted to rotate said bolts in the standard and the other set being adapted to impart a revolving motion to said table, a worm gear drive .tor turning the means supporting the cutter to an amount corresponding to the circular pitch of the cutter teeth, this drive being independent from the turning means ct -said revolving table, a friction drive actuating said worm gear drive, and means to automatically throwing in and out said friction drive.

In testimony that I claim the foregoing as my invention, 1 have signed my name in presence of two subscribing witnesses.

GEORG BICNICKE.

Witnesses CARL GRUND, JEAN GRUND. 

